1. Field
Certain aspects of the disclosure relate generally to wireless communications systems and, more particularly, to techniques for managing radio bearers in telecommunication networks with relays.
2. Background
Wireless communication systems are widely deployed to provide various types of communication content such as voice, data, and so forth. These systems may be multiple-access systems capable of supporting communication with multiple users by sharing the available system resources (e.g., bandwidth and transmit power). Examples of such multiple-access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, 3GPP Long Term Evolution (LTE) systems including E-UTRA, and orthogonal frequency division multiple access (OFDMA) systems.
Generally, a wireless multiple-access communication system can concurrently support communication for multiple wireless terminals that communicate with one or more base stations via transmissions on forward and reverse links. The forward link (or downlink) refers to the communication link from the base stations to the terminals, and the reverse link (or uplink) refers to the communication link from the terminals to the base stations. This communication link may be established via a single-in-single-out, multiple-in-signal-out or a multiple-in-multiple-out (MIMO) system.
Wireless communication systems may comprise a donor base station that communicates with wireless terminals via a relay base station. The relay base station may communicate with the donor base station via a backhaul link and with the terminals via an access link. In other words, the relay base station may receive downlink messages from the donor base station over the backhaul link and relay these messages to the terminals over the access link. Similarly, the relay base station may receive uplink messages from the terminals over the access link and relay these messages to the donor base station over the backhaul link. The relay base station may, thus, be used to supplement a coverage area and help fill “coverage holes.”
Generally, a bearer is defined as a packet flow with a defined Quality of Service (QoS) between a gateway and a user equipment (UE). In telecommunication networks with relay nodes, bearers employed for packet flows between a relay node and its served UEs (referred to as “Uu bearers”) are carried by data radio bearers (DRBs) employed for relay packet flows between the relay node and a donor base station (DeNB) associated therewith (referred to as “Un data radio bearers”). Additionally, Un data radio bearers may carry data flows for relay node signaling.